An investigation of graphite PEEK composite under compression with a centrally located circular discontinuity

The failure characteristic of graphite polyetheretherketone (Gr/PEEK) under compression with a centrally located circular discontinuity was investigated through experimentation and a nonlinear ply-by-ply finite element technique. The stacking sequence of the laminates investigated were: 0 °₁₆], 90 °₁₆], ±45 °]_4S 0 °/90 °]_4S, and 0 °/ ± 45 0°/90 °]_2S. In the experimentation, 90 °]₁₆, 0 °/90 °]_4S, and 0 °/ ±45 °/90 °]_2S laminates, as well as three of the 0 °]₁₆, failed due to a crack that was normal to the loading direction and initiated from the edge of the hole progressing to the outer edges of the specimen. The ±45 °]_4S specimens failed to support the load due to an internal crack that originated from the hole's edge and then traveled at an angle of about 42% to the direction of loading. The finite element method used to analytically model the failure of Gr/PEEK accurately modeled the response of the specimens tested experimentally.